Study on Intrinsic Loss of Unipola Power Device due to Main Junction Capacitance

Abstract

The converters with high power output density has been envisioned for next generation. The key to realize that is operation at very high switching speed and utilization of ultra low loss of power semiconductor devices in wide bandgap semiconductor e.g. Silicon Carbide and superjuction. The power loss by main junction capacitance, C_oss intrinsically structured inside the device has been reported but the quantitative study is not adequate. In this study, for 3kW converters, the loss by C_oss is theoretically and experimentally proved using heat measurement with resistive and inductive load chopper circuit with 500V Si-MOSFET and 600V Silicon Carbide Schottky barrier diode. Moreover since large loss remained other than already known loss factors has been quantitatively revealed, and it is suggested that this remained loss will be a next target for further reduction of switching loss.